Hi all,
In my local installation of Moodle 2.7beta (Build: 20140411), I wanted to add messages in the navbar. I used a part of the code from Bootstrap, a parent theme of Shoehorn - thank you Gareth for providing the code. This is how it looks now:

At the moment I am content with messages next to the custom menu and not to the login details. I added a zip-file that contains the new core_renderer in Bootstrapbase\renderers of Moodle 2.7dev with the code for messages at the top. The highlighted code in the attached PDF-file shows the lines which I copied and pasted from Bootstrap. I just wanted to share this with the Moodle community in case someone else is interested to use the Clean theme with this minor modification.
With kind regards,
Hartmut